This invention relates to the segregation of molded parts, and, more particularly, to the segregation of molded production parts from accompanying by-product parts that are formed in the molding process.
In the production of parts by molding, molten material is forced into the cavities of a mold through opeings called sprues and channels called runners. When the material has cooled sufficiently, the mold is opened and the desired product is expelled, along with the by-product formed in the runner and sprue. The latter is waste which must be segregated from the production parts. This can be done manually, but that is time consuming and inefficient.
To curtail the extent of the manual effort, a number of techniques have been devised for the automated segregation of the desired mold product from the undesired product. A machine for one such technique is disclosed in U.S. Pat. No. 3,663,142 which issued May 16, 1972. The machine makes use of a conveyor belt which feeds the entire product from the mold to a "separator" or segregator in the form of coaxial disks on a shaft at the end of, and perpendicular to, the feed axis of the conveyor belt. The disks are spaced so that the desired product will fall between them and be collected, but the by-product will not. It is instead conveyed by scalloped or serrated peripheries of the disks to a waste collection station. In this arrangement, it is also desirable to have a second set of disks which are interposed with respect to the first set of disks.
At a variant of the disk system, a drum with flexible lift pins is substituted for the disks. The spacing of the pins is in accordance with the spacing of the disks, so that the desired objects fall between the pins, while the waste product is carried by the pins to a collection position.
While both the disk and drum systems are a considerable improvement over manual segregation, they require a belt conveyor and separate drives for the conveyor and the segregator.
Furthermore, the disks, the drum, the belt conveyor, and the requirement of two separate drives add to the mechanical complexity.
In addition, when fine filaments are produced during molding they can get caught on the disks, the hub of the disks and the pins of the drum. When this happens, they cause interference with the desired segregation of wanted and unwanted parts.
Moreover, while the drum and disk arrangements work well when there is a sufficient differentiation between the wanted and unwanted parts, they are not always suitable when the parts are small.
Finally, when the mold is changed, it is often necessary to change the segregator. However, the disks and drum segregators are not as easily changed as the mold, causing delays when production is switched from one product to another.
Accordingly, it is an object of the invention to facilitate the segregation of molded parts. A related object is to facilitate the segregation of wanted and unwanted parts. Another related object is to facilitate the segregation of production parts from the sprue and runner parts produced during molding.
Another object is to achieve the automated segregation of molded parts without the need for a conveyor belt. A related object is to realize automated segregation without the need for separate conveyor and segregator drive units.
A further object is to achieve automated segregation of molded parts without employing either disk or drum segregators. A related object is to reduce any tendency for filaments formed during molding to cause interference in the segregation of molded parts.
Yet another object is to facilitate the interchange of segregators when required by virtue of a change in production molds. Still another object is to facilitate the segregation of comparatively small parts.